improve infinite scrolling so it keeps paginating until you have a scrollbar (if it can)

This commit is contained in:
Matthew Hodgson 2014-08-16 22:05:31 +01:00
parent f1d140eea8
commit 8c69eff14c
1 changed files with 28 additions and 17 deletions

View File

@ -36,10 +36,11 @@ angular.module('RoomController', [])
$scope.userIDToInvite = "";
var scrollToBottom = function() {
console.log("Scrolling to bottom");
$timeout(function() {
var objDiv = document.getElementById("messageTableWrapper");
objDiv.scrollTop = objDiv.scrollHeight;
},0);
}, 0);
};
$scope.$on(eventHandlerService.MSG_EVENT, function(ngEvent, event, isLive) {
@ -59,12 +60,12 @@ angular.module('RoomController', [])
$scope.paginateMore = function() {
if ($scope.state.can_paginate) {
// console.log("Paginating more.");
paginate(MESSAGES_PER_PAGINATION, false);
paginate(MESSAGES_PER_PAGINATION);
}
};
var paginate = function(numItems, toBottom) {
// console.log("paginate " + numItems + ", " + toBottom);
var paginate = function(numItems) {
// console.log("paginate " + numItems);
if ($scope.state.paginating) {
return;
}
@ -75,11 +76,7 @@ angular.module('RoomController', [])
var originalTopRow = $("#messageTable>tbody>tr:first")[0];
matrixService.paginateBackMessages($scope.room_id, $scope.state.earliest_token, numItems).then(
function(response) {
// hacky bodge to ensure we always scroll to the bottom on the first pagination
if (!$scope.events.rooms[$scope.room_id]) {
toBottom = true;
}
var firstPagination = !$scope.events.rooms[$scope.room_id];
eventHandlerService.handleEvents(response.data.chunk, false);
$scope.state.earliest_token = response.data.end;
if (response.data.chunk.length < MESSAGES_PER_PAGINATION) {
@ -88,11 +85,28 @@ angular.module('RoomController', [])
$scope.state.can_paginate = false;
}
if (toBottom) {
console.log("Scrolling to bottom");
$scope.state.paginating = false;
var wrapper = $("#messageTableWrapper")[0];
var table = $("#messageTable")[0];
// console.log("wrapper height=" + wrapper.clientHeight + ", table scrollHeight=" + table.scrollHeight);
if ($scope.state.can_paginate) {
// check we don't have to pull in more messages
// n.b. we dispatch through a timeout() to allow the digest to run otherwise the .height methods are stale
$timeout(function() {
if (table.scrollHeight < wrapper.clientHeight) {
paginate(MESSAGES_PER_PAGINATION);
scrollToBottom();
}
}, 0);
}
if (firstPagination) {
scrollToBottom();
}
else {
// lock the scroll position
$timeout(function() {
// FIXME: this risks a flicker before the scrollTop is actually updated, but we have to
// dispatch it into a function in order to first update the layout. The right solution
@ -100,12 +114,9 @@ angular.module('RoomController', [])
// http://stackoverflow.com/questions/23736647/how-to-retain-scroll-position-of-ng-repeat-in-angularjs
// however, this specific solution breaks because it measures the rows height before
// the contents are interpolated.
var objDiv = document.getElementById("messageTableWrapper");
objDiv.scrollTop = originalTopRow ? (originalTopRow.offsetTop + objDiv.scrollTop) : 0;
wrapper.scrollTop = originalTopRow ? (originalTopRow.offsetTop + wrapper.scrollTop) : 0;
}, 0);
}
$scope.state.paginating = false;
},
function(error) {
console.log("Failed to paginateBackMessages: " + JSON.stringify(error));
@ -242,7 +253,7 @@ angular.module('RoomController', [])
}
);
paginate(MESSAGES_PER_PAGINATION, true);
paginate(MESSAGES_PER_PAGINATION);
},
function(reason) {
$scope.feedback = "Can't join room: " + reason;
@ -284,6 +295,6 @@ angular.module('RoomController', [])
};
$scope.loadMoreHistory = function() {
paginate(MESSAGES_PER_PAGINATION, false);
paginate(MESSAGES_PER_PAGINATION);
};
}]);